Apple changed their in-app purchase policy and ebook vendors were forced to close their integrated stores. Rather than just direct you to the web browser to buy ebooks, Amazon created a web-based ebook reading experience where you can buy ebooks and read them in online or offline modes right from within the browser.

Amazon Kindle Cloud Reader now available for web-based ebook reading

Apple changed their in-app purchase policy and ebook vendors were forced to close their integrated stores. Rather than just direct you to the web browser to buy ebooks, Amazon created a web-based ebook reading experience where you can buy ebooks and read them in online or offline modes right from within the browser.